1. Field of the Invention
The present invention is related to a lithography system.
2. Background Art
Pattern generators are used in lithography systems to pattern substrates during an exposure process. Example lithography systems include, but are not limited to, reflective or transmissive maskless, immersion, and photolithography system. Example substrates include, but are not limited to, semiconductor wafers, flat panel display substrates, flexible substrates, and the like. Light interacting with an illumination spot on the pattern generator becomes patterned. The patterned light is projected using a projection optical system onto one or more target areas of the substrate during the exposure process to form features on the substrate.
FIG. 14 shows a portion of a conventional lithography system 1400. System 1400 includes pattern generator 1402 that directs patterned light through a pattern generator group of optical elements 1404, an intermediate group of optical elements 1406, a substrate group of optical elements 1408, and onto a substrate 1410. System 1400 includes a fixed magnification at an object plane 1412 and a fixed distance between object plane 1412 and an image plane 1414. For semiconductor fabrication this was possible because both pattern generator 1402 and substrate 1410 had relative sizes that allowed for a fixed magnification and distance.
However, for flat panel display fabrication using a fixed magnification is no longer desirable because in flat panel display fabrication substrate 1410 is typically many times larger than a size of pattern generator 1402. For example, in flat panel display fabrication pattern generator 1402 can have 1 million pixel areas or active areas, while substrate 1410 can have billions or trillions of pixels areas of the same size. Thus, in flat panel display fabrication substrate 1410 can be about 3 to 6 orders of magnitude larger than pattern generator 1402. Having a fixed magnification results in only being able to pattern one sized feature at a time, which substantially decreases throughput. Throughput is low because various sets of features have different sizes, and with a fixed magnification only one size feature can be pattern during a single exposure.
Therefore, what is needed is a lithography system and method that allow for an increased throughput through patterning of all feature sizes in during each exposure, possibly patterning features over an entire surface of a substrate substantially at a same time. What is also needed is a lithography system and method that can allow for various magnifications, numerical apertures, resolutions, and/or working distances between various parts of the lithography system.